Clamping device



June 2, 1936.. STAHL 7 2,043,125

CLAMPING DEVICE Filed Aug. 18, 1934 INVENFUR TRANK E.

Patented June 2, 1936 7 UNITED PATENT ori ice 2,043,125 BLAMPING DEVICE Frank E. Stall-l, Tonawanda, N. Y; ass'ignor to Columbus Mc'Kinhon Chain Corporation, 'Tonawanda, N. 'Y., a corporation 'of'New York Applicatienriugust .18, 1934, Serial'No. 740,523

'3 Claims.

My invention relates in general to clamping devices, and more particularly to a clamp for use upon jigs.

It is well known to those skilled in the art, that due to the variable qualities of castings, the crdinary clamp 'used in-jigs cannot be made to effectively clamp because of such variation. -It'is furthermore well known that in such clamps an eccentric or cam-shaped surface is usually employed, which has its maximum holding power only at a definite point in its rotation. If, therefore, the casting is too thick, this maximum clamping position cannot be reached; or, if the casting is too thin, the clamp will not hold.

' In order to overcome the above disadvantages found in the ordinary types of jig clamps, it has been an object of my invention to provide a. clamp which shall be conveniently adjustable to various thicknesses of castings, whereby the clamp may always be adjusted to the position where it will produce its maximum clamping action.

Another object has been to provide adjusting means for a jig clamp which will not in any wise interfere with the operation of the clamp or require the use of any tools to effect the adjustment thereof.

Moreover, my device is of such a nature that it may be easily and quickly manipulated by the workman without loss of time.

Furthermore, I have provided, in my device, anti-friction rollers located in that portion of the cam face which receives the final pressure.

The above objects and advantages have been accomplished by the device shown in the accompanying drawing, of which:

Fig. 1 shows a side elevation of my invention as applied to a jig.

Fig. 2 is a plan view thereof.

Fig. 3 is a vertical, sectional view, taken on line 33 of Fig. 1.

In the drawing I have indicated, in a fragmentary manner, the base 5 of a jig which is provided with a surface 6 on which the casting l to be machined is placed. In this form of jig a shoulder 8 is provided which is substantially the same height as the casting I being operated upon. The jig obviously has other parts for the support of drills, reamers, and the like, for operation upon the casting but, since these do not form a part of my invention they are not shown or described.

The clamping plate 9 of the jig is shown as resting upon the shoulder 8 thereof and upon the casting I. A clamping washer Ill is located on top'of the jig plate and a clamp bolt I I, having its upper end screwthreaded, is carried by the jig and extends up through the plate '9 .and the washer I0 to a point some distance above the washer. The clamping plate 9 is provided with an elongated slot l2 so that the plate ,9 may be adjusted laterally to the desired position. viously, the washer ID is provided with an opening for passage over the bolt.

Arranged on the upper end of the clamp bolt l l I is an adjusting nut l5 which is preferably .provided with a cylindrical body portion [6 and a knurled finger engaging portion 11., Carried by the clamp bolt and arranged between the adjusting nut l5 and the washer I0 is a trunnion block l8. This block is provided with a central aperture for passage over the bolt, and it is formed on opposite sides with trunnions IS.

The clamping lever 25 comprises a handle 26 which is carried on the outer end of a bifurcated body portion 21. This portion is preferably provided with an integral arm 28 and with a detachable arm 29. These arms extend forwardly and each is provided with an aperture 30 for the reception of one of the trunnions IS. The apertures 30 are arranged near the top surfaces of the arms 29, and these arms are formed on their lower forward edges with cam surfaces 3|, which surfaces are arranged to engage with the upper surface of the washer It so that they will be in locked position when the clamping lever 25 has reached the position shown in the drawing. An anti-friction roller 32 is located in each of these cam faces and so positioned that it will come into engagement with the clamping washer when the operating handle has reached its maximum clamping position, as shown in the drawing. These rollers are let into circular recesses 33 formed from the outside faces of the arms. through the arm 29 and thereby a retaining wall 31 is provided. In order to keep the rollers in place a lock plate 34 is carried by each of the arms and is fastened in place by means of a screw 35. When the device is to be put into use, the casting 1 is placed in its proper position upon the surface 6 of the jig and the clamping plate is rested upon the shoulder 8 and the top of the casting. The slot l2 in the plate makes this adjustment possible. Obviously, the clamping lever 25 has previously been moved to its unlocked position where the cam face 3| will not be acting upon the washer l0. With the clamping plate in position the clamping lever 25 is operated to These recesses 33 only part way extend bring it to the position shown in Fig. 1 and during this operation the cam face 3| will ride over the top surface of the clamp washer l0 and such movement will serve to force the trunnion block l8 up against the bottom surface of the portion l6 of the adjusting nut. When the clamping lever comes into its proper locking position, the anti-friction rollers 32 are brought into engagement with the washer l0 and the work piece is thus firmly clamped in the jig. If the work piece is thick and the clamping lever does not move to its full clamping position, the workman may easily and quickly unscrew the adjusting nut l1 so that the clamping lever may be brought to its proper position. Likewise, if the casting is thin and the clamping lever does not clamp sufficiently, the adjusting nut may be tightened slightly. In other words, the adjustment of the lever to bring it to its proper and most efficient clamping position may be easily done for each casting, if necessary, without loss of the workmans time and without the use of any wrenchesor tools.

Obviously, some modifications of the details herein shown and described maybe made without departing from the spirit of my invention or the scope of the appended claims, and I do not, therefore. wish to be limited to the exact embodiment herein shown and described, the form shown being merely a preferred embodiment thereof.

Having thus described my invention, what I claim is:

1. The combination with a jig, of clamping means, comprising a clamp bolt carried by the jig, a clamping plate and a clamping washer carried by the bolt, a knurled adjusting nut carried by the upper end of the bolt, a trunnion block rotatably mounted upon the bolt and arranged between the clamping nut and the washer, and a clamping lever pivotally mounted upon the trunnion block and formed with camshaped faces engageable with the washer, said nut being'adjustable independently of the clamp- I ing lever.

2. A clamping device comprising a stationary clamp bolt, a trunnion block rotatably mounted upon the bolt, a clamping lever pivotally mounted upon the trunnion block and having a camshaped face, and adjusting means carried at the upper end of the clamp bolt and operable independently of the clamping member and the trunnion block, whereby the working position of the clamp may be accurately adjusted.

3. The combination with the base of a jig, of clamping means comprising a clamping plate, a stationary bolt carried by the base, a block slidably carried by the bolt, a clamping lever pivotally carried by the block and having cam-shaped faces for engagement with the clamping plate, abutment means carried by the upper end of the bolt and engageable with the block, and means independent of the clamping member and the trunnion block for adjusting the position of the abutment, whereby the working position of the clamp may be accurately adjusted.

FRANK E. STAHL. 

